Muffler with expansion chamber defining centrifugal flow path



March 29 1966 R. B. HILL 3,243,011

MUFFLER WITH EXPANSION CHAMBER DEFINING CENTRIFUGAL PLOW PATH Filed July 22, 1964 RAYMON B. HILL INVENTOR.

L 6M W ATTORNEYS United States Patent O M 3,243,011 MUFFLER WITH EXPANSION CHAMBER DE- FINING CENTRIFUGAL FLOW PATH Ramon B. Hill, 12415 SW. 186th St, Miami, Fla. 33157 Filed July 22, 1964, Ser. No. 384,397 5 Claims. (Cl. 181-58) This invention relates to improvements in mufilers for exhaust gases. It is particularly useful as a mufiler for exhaust gases from internal combustion engines of heavy trucks and tractors, but is not limited to such use.

-It is customary for exhaust gases from engines of trucks and tractors to be passed from the engine through an elongated mufiler and thence through a substantially vertical exhaust pipe to the atmosphere.

The exhaust gases normally pass through an exhaust pipe connecting a muffler inlet to an exhaust manifold of the engine. This ex.- haust pipe usually includes at least one elbow or substantrally right angle bend. The mufiier is provided with an outlet which is ordinarily in substantially the same hori- 1 zontal plane as the inlet, and another elbow or substantially right angle bend in the tail pipe is provided to direct the tail pipe upward. The mufilers used usually are cylindrical or oval in cross section and are provided with internal baflles, usually perforated, and so arranged that the that replacement of elbows is a large item of upkeep expense with most companies engaged in highway trucking operations. Elbows and direct bafiling also increase back pressure on the exhaust gases; and tend to decrease the useful life of the mufiler.

The presence of el- It is an object of this invention to provide a mufller which does not require exhaust pipes or tail pipes containing elbows or sharp bends.

Another object is to provide a muffler in which a change in direction of exhaust gases occurs gradually during expansion of the gases in a chamber of large volume. An-

other object is to provide a mufller which applies little back pressure on exhaust gases.

Another object is to provide a muffier in which a large part of the muffiing function is performed by streams of exhaust gases impinging upon each other.

Another object is to provide a mufiler which has high mufiiing effect in a small volume.

Another object is to provide a muffler which has very long useful life.

Other objects and advantages and features of this invention will be apparent to one skilled in the art upon a consideration of the written specification, the attached claims and the annexed drawing.

The rnufiler of the present invention includes a shell which preferably is elliptical in cross section although it.

may have other cross sectional shapes as for example, circular or rectangular with the corners rounded. An elliptical cross section is preferred because it gives the greatest muffling power in the smallest volume. The shell preferably includes a substantially vertical side wall which may be straight or curved in vertical elevation and a pair of end closure members, preferably domed, cooperating with the side wall to close the shell.

The vertical side wall has a horizontally elongated inlet opening which extends for a major part of the length Patented Mar. 29, 1966 of the mufiler, i.e., of the ellipse defined by the side wall, and the inlet opening is parallel thereto. An inlet conduit for exhaust gases extends horizontally along-the side opening in gas-type contact with the wall of the shell surrounding the opening, The conduit has an elongated lateral outlet opening and registering with the inlet opening and preferably has an inner end substantally tangent to the side wall when the side wall is elliptical, or at a very small angle to the side wall if the side wall is of rectilinear shape. An outer end of the conduit is adapted to be connected to an exhaust pipe from an internal combustion motor and may be slightly enlarged and slotted to make a slip fit upon the end of such exhaust pipe, or may then have any other type of connecting means desired.

Perforate battles are disposed vertically in the shell providing a baffled zone in the shell opposite the inlet and at a level of the inlet opening. 'These batfies do not extend vertically all the way across the shell but provide a completely unbatfled zone extending across the shell below the bafiles.

These bafiles are usually two or three in number depending upon the size of the mufiler. When three are used the first ,batfie preferably extends across the muffler from a point adjacent the end of the inet opening to an opposite wall. This baffle may be flat or arched outward toward the midpoint of the muffler as desired. The second ballle extends from the junction point of the first bafile with the side wall opposite the inlet, is arched outward toward the longitudinal centerline of the mufiler and extends to a second point on the wall opposite the inlet opening so that the baffles are of approximately the same length. The third bafile extends from the second point on the side wall of the muffler to a tail pipe conduit at a point on the conduit approximately in the centerline of the muffler.

The tail pipe conduit extends vertically downward through an upper end of the muffler at a location substantially at the focus of the ellipse defined by the side wall nearest the beginning of the inlet opening. The tail pipe conduit extends downward through the baffle zone to the level of the bottom of the baffies where it communicates through its open end with the unbafiled zone extending across the mufiler.

It will be seen that with this arrangement a stream of hot high velocity exhaust gases entering through the exhaust pipe conduit will begin to expand, cool and slow down at difierent rates after they reach the beginning of the inlet opening. If different parts of this stream be considered as laminae it will be seen that the direction of expansion of the laminae also is different. Gas travel-ing at high velocity along the wall of the connector nearest the shell expands outward into the shell immediately when it arrives to the beginning of the inlet opening through the side wall, while the laminae more and more remote from the shell continue onward at high velocity until they arrive at a location further from the inital edge of the inlet opening until the last gases are discharged from the connector in a direction substantially tangent to the ellipse defined by this said wall.

As a result the gases within the shell are given a swirling motion around the interior of the elliptical shell but the swirling motion is highly turbulent. The swirling turbulent gases are further broken up and turbulence is increased by contact with the perforated baffles. That part of the gas which passes through perforations in the first two baffles is directed downward into the unbaflled space. It will be seen also that there is expansion of exhaust gases downward in the muffler so that a part of the stream does not reach the baffle at all but passes 3 directly downward into the unbaffled space and flows upward through the tail pipe conduit from that location.

A part of the gases passing through perforations in the third baffie also expand downward into the unbaffied space while other parts pass through lateral openings in the tail pipeconduit within the baffled zone in the form of jets entering at substantially right angles to the direction of flow of the stream gases entering the open bottom of the tail pipe conduit communicating with the unbaflied zone. A portion of the stream ,gases entering the inlet also passes directly to the lateral openings in the tail pipe conduit so that a very high degree of turbulence is presopening in conduit 12 are of such length as to extend ent within the tail pipe conduit and much of the controlled expansion of exhaust gases is due to the high degree of turbulence within the tail pipe conduit.

Controlled expansion, cooling, and change direction of the gases thus occurs without the use of direct baffling of all gases. No points are present in the muffler where there is a sharp change in direction of high velocity hot gases, and thus there is no concentration of corrosive and erosive effects.

The muffler may, if desired, have more than one inlet opening on the same side or on opposite sides of the shell, and tail pipe conduits extending through both ends of the shell. When multiple inlets are used, and are located at different levels in the 'mufller, separate series of baffles are arranged to provide separate baflled zones at the level of each inlet. It is preferred that a single, central, unbafiled zone extending across the central section of the muffler between the bottom and to edges of .upper and lower series of baffles be provided. In this arrangement separate tail pipe conduits extend through opposite ends of the shell, through the corresponding bafiled zone to the central unbafiled zone.

This arrangement is'substantially the same as two singl inlet mufflers placed end to end with separating end closure members omitted.

It is particularly useful when more than one exhaust manifold 'is present, as for example, in a V8 engine.

The construction of the mufiier of the present invention can be best appreciated by reference to a detailed description of one preferred type of mufller shown in the attached drawings wherein:

'FIG. 1 shows one preferred muffler constructed according to principles of this invention illustrating partially in horizontal cross section, a highly effective arrangernent of inlet conduit,rshell, battle, and tailpipe;

FIG. 2 is a vertical section through .the muffler of FIG. 1 on the line 2-2;

FIG. '3 is a perspective viewof thesame muffler on reduced scale.

Since it is necessary to orientate elements of the improved mufiler with respectto each other for convenience in the description, the terms vertical, horizontal,

lateral, above and below are used in describing the muffier of the present invention in a special restricted sense in this specification and claims, to mean the corresponding'directions and relationships as illustrated in FIG. 2 of the drawings,'although it is to be understood .tact with the Wall of the shell surrounding the opening.

The conduit has a lateral elongate outlet opening registering with the inlet opening 11. The inner end 13 of the inlet conduit preferably is substantially tangent to shell 6 and the elongate opening 11 and'the matching for a major part for the length of ellipse 7.

Within the shell a plurality of perforated vertical baffles are disposed to provide a baffied zone within the shell .at the level of the inlet opening. In the preferred arrangement of bafiles shown, three bafiles 14, 15 and 16 are used. The baffle 14 extends from a point within the shell adjacent to the tangent end 13 of inlet conduit 12 and is arched across the baffle to a point 17 on the wall 6 where it joins a second baffle 15 arched inward from point 17 to point 18 on the wall of the shell. The bafile 16 extends from point 18 to a tail pipe 19. It is preferred that these bafiles be of approximately equal size and length. I

Baffles 14, 15 and 16 extend vertically from a point adjacent to the upper level of side wall 6 downward to provide a large unbafiled zone extending all the way across the interior of the shell at a level below the lower edges of the bafiles. The unbaflled, unobstructed Zone is of substantial size, as for example, approximately'% the total volume of the shell. The tail pipe 19 extends vertically through end member 8 through the baffled zone 21 to theunbaffied zone 22. Pipe 19 has an open lower end 23 communicating 'with zone 22 and has numerous lateral openings 24 communicating with the bathed zone21.

The tail pipe conduit has a suitable connection 25 adapted to be connected to a vertical tail pipe 26 extending upward to discharge exhaust gases into the atmosphere. The inlet conduit 12 also has an end remote from the shell 5 illustrated as an enlarged and slit end 27, adapted to be connected with an exhaust pipe 28.

In operation a stream of exhaust gases, as for example, from an internal combustion engine is introduced through exhaust pipe 28 into the inlet conduit 12 at high velocity. The inlet opening into the shell is very long and is in register with an elongate outlet from exhaust pipe 12 so that the high velocity gases begin to expand outward when they reach the point 29. Some of the gas immediately begins to expand laterally into the shell into the direction indicated by the arrow 30 while other portions of the gas continue onward in thedirection indicated by the arrows 31 and 32. Ultimately all the gas entering through inlet conduit 12 and passing in the direction shown at 31 and 32 moves outward as shown by the arrows 33 and 34 in the shell.

A large portion of the gases thus are discharged toward the battles 14-, 15 and 16, but-since the distance between theinlet opening and baffles is substantial, entering gases, also expand downward into this unbaffled space below the baffles. Gases passing through perforations in baflies 14 and 15 also move downward into the unobstructed space below the baifies.

As the high velocity gases move outward into the shell they begin to expand, to cool and to slow down at different rates, and directions of expansion are different after they have reached the point 31 By the time the gases from inlet conduit 12 have reached point 35 they have begun to curve due to the curvature of inlet conduit 12 and as they whirl around the interior of the elliptical shell they are broken up by passing through and over the perforated bafiies. In order for these whirling gases to be expelled through the outlet they must go either through the openings 24 into tail pipe conduit 19 or downward into the unobstructed zone 22 and upward through the open bottom of conduit 1?. The proportion of gases tak ing these ultimate paths obviously will be dependent upon the resistance offered by the two paths. A large proportion of the gas will pass downward into space 22 and upward through conduit 19 where it encounters jets of exhaust gas entering through openings zd at substantially right angles'to the flow of gases within conduit 19. Impingement of jets entering through openings 24 uponthe stream of gas flowing upward in tail pipe conduit 19 results in turbulence, and a great deal of the mutlling function is performed by turbulence of the gases. There is no sharp change in direction of an entire stream of hot gases flowing at high velocity at any point within the muffler. Expansion takes place gradually and is accompanied by cooling by simultaneous change of flow. The change in direction is gradual rather than sharp and no direct bafiiing occurs. As a result mufflers of this type have a very long useful life and are free from the disadvantages due to high back pressure caused by direct bafliing.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. A muffier comprising in combination a vertical shell having a horizontally elongate inlet opening in a side thereof for a distance equivalent to a major part of the length of the rnufiier; an inlet conduit for exhaust gases extending horizontally along said opening in gas-tight contact with the wall of said shell surrounding said opening, said conduit having a lateral elongate outlet opening registering with said inlet opening; perforate baffles disposed vertically in the shell providing a baffled zone in said shell at the level of said openings and an unbafiied zone extending across the interior of the shell below said baffles; and a tail pipe conduit extending vertically through an end of the shell, through said baffled zone to said unbaffied zone at a location near an end of the shell nearest an initial end of said inlet opening and on a centerline of the shell, said tail pipe conduit having an, open inner end communicating with the unbatfied zone and numerous lateral openings communicating with said bafiied zone.

2. A muflier comprising in combination a vertical shell substantially elliptical in horizontal cross section having a horizontal elongate opening in a side thereof extending for the major part of the length of an ellipse defined by the sidewall; an inlet conduit extending horizontally along said opening in gas tight contact with the wall of said shell surrounding said opening, said conduit having an elongate lateral outlet opening registering with said inlet opening; perforate baffles disposed vertically in the shell providing a bafiled zone in said shell at the level of said openings and an unbafiled zone extending across said shell below said bafiles; and a tail pipe conduit extending vertically through an end of the shell substantially at a focus of the ellipse nearest an initial end of said inlet opening extending through the said bafiled zone to said unbatfled zone, said tail pipe having an open inner end communicating with the unbafiled zone and numerous lateral openings communicating with said bafiled zone.

3. A muffler comprising in combination a vertical shell having a horizontally elongate inlet opening in a side thereof extending for a major part of the length of said shell; an inlet conduit for exhaust gases extending horizontally along said opening in gas tight contact with the walls of said shell surrounding said opening, said conduit having an elongate opening registering with said inlet opening; perforate baffles disposed vertically in the shell providing a baffled zone in said shell at the level of said openings and an un-baffled zone extending across the shell below said baffi-es, said unbaflled zone having a volume approximately /2. the total volume of said muffler; and a tail pipe extending vertically through an end of the shell, and through said bafiied zone to the unbaffied zone at a location on the centerline of the shell and near an end of the shell, said tail pipe having an open end communicating With the unbaflied zone and numerous lateral openings communicating with said baflled zone.

4. The mufiier of claim 3 in which the baflies extend downward from a level adjacent the top of the side Wall of the shell and a first baflie extends from a point on the interior of the shell adjacent to an inner end of the inlet opening to a point on the shell across from said inlet, and another baffie extends from a point on the shell across from the inlet to the tail pipe conduit at a point thereon substantially on the longitudinal centerline of the shell.

5. The mufiier of claim 4 having three bafiles of approximately equal length, namely a first bafiie extending from a point on the interior of the shell adjacent to an inner end of the inlet opening to a first point on the shell across from said inlet; a second baffle arched toward the centerline of the shell extending from said first point to a second point on the shell across from said inlet, and a third baffle extending from said second point to a point on the tail pipe conduit adjacent the centerline of the shell.

References Cited by the Examiner UNITED STATES PATENTS 1,653,934 12/1927 Stockfleth et al. 18l58 X 2,511,713 6/1950 Hoyle et al.

FOREIGN PATENTS 1,256,568 2/ 1961 France.

LEO SMILOW, Primary Examiner, 

1. A MUFFLER COMPRISING IN COMBINATION A VERTICAL SHELL HAVING A HORIZONTALLY ELONGATE INLET OPENING IN A SIDE THEREOF FOR A DISTANCE EQUIVALENT TO A MAJOR PART OF THE LENGTH OF THE MUFFLER; AN INLET CONDUIT FOR EXHAUST GASES EXTENDING HORIZONTALLY ALONG SAID OPENING IN GAS-TIGHT CONTACT WITH THE WALL OF SAID SHELL SURROUNDING SAID OPENING, SAID CONDUIT HAVING A LATERAL ELONGATE OUTLET OPENING REGISTERING WITH SAID INLET OPENING; PERFORATE BAFFLES DISPOSED VERTICALLY IN THE SHELL PROVIDING A BAFFLED ZONE IN SAID SHELL AT THE LEVEL OF SAID OPENINGS AND AN UNBAFFLED ZONE EXTENDING ACROSS THE INTERIOR OF THE SHELL BELOW SAID BAFFLES; AND A TAIL PIPE CONDUIT EXTENDING VERTICALLY THROUGH AN END OF THE SHELL, THROUGH SAID BAFFLED ZONE TO SAID UNBAFFLED ZONE AT A LOCATION NEAR AN END OF THE SHELL NEAREST AN INITIAL END OF SAID INLET OPENING AND ON A CENTERLINE OF THE SHELL, SAID TAIL PIPE CONDUIT HAVING AN OPEN INNER END COMMUNICATING WITH THE UNBAFFLED ZONE AND NUMEROUS LATERAL OPENINGS COMMUNICATING WITH SAID BAFFLED ZONE. 